Low-noise fiber-optic amplifier utilizing polarization adjustment

摘要

A fiber-optic amplifier with reduced noise characteristics is provided. A polarization beam splitter/recombiner splits an input signal beam into two orthogonally polarized optical signals and recombines the separately treated signals. A phase controller compensates for optical path differences that result from dividing the input signal beam into two different paths. A wavelength division multiplexing coupler couples a pump laser beam with the input signal beam. A polarization maintained doped optical fiber amplifies the split optical signals while maintaining their original states of polarization. A linear polarizer rejects from each amplified split optical signal the noise with polarization orthogonal to the amplified signal. By suppressing such noise power, a portion of amplified spontaneous emission with polarization orthogonal to the signal is suppressed, thereby reducing the total output noise power.